An Inexpensive Conceptual Training Model for Transvenous Pacemaker Placement.

INTRODUCTION: Emergent transvenous (TV) pacemaker placement can be life-saving, but it has associated complications. Emergency medicine (EM) educators must be able to teach this infrequent procedure to trainees. METHODS: We constructed a conceptually-focused, inexpensive training model made from polyvinyl chloride pipes and connectors, vinyl tubing, and a submersible pump. Cost of the model was $51. We tested the model with a group of 15 EM residents. We then asked participants to complete a survey reporting confidence with the procedure before and after the session. Confidence was compared using a Wilcoxon matched-pairs test. RESULTS: Confidence improved after the session, with a median confidence before the session of 2 (minimally confident; interquartile range [IQR] 1-3) and a median confidence after the session of 4 (very confident; IQR 3-4, p=0.001). All residents agreed that the model helped them to understand the process of placing a TV pacemaker. CONCLUSION: Our TV pacemaker placement model was inexpensive and allowed for practice of a complex emergency procedure with direct visualization. It improved trainee confidence.

The effect of air exposure on leucocyte and cytokine activation in an in-vitro model of cardiotomy suction.

INTRODUCTION: Cardiopulmonary bypass (CPB) is known to cause a systemic inflammatory and immune response. OBJECTIVE: An in-vitro model of cardiotomy suction was designed to quantify the effects of incrementally increased air-blood exposure on leucocyte marker CD11b and cytokine activation in two common anticoagulants, heparin and citrate. METHODS: Fresh human blood was exposed to increasing amounts of air flow for ten minutes. Leucocyte and cytokine levels were measured prior to and after ten minutes of air flow. Cytokine levels were also measured after air exposure when incubated for 24 hours at 37oC. RESULTS: Leucocyte activation, measured by CD11b, was elevated between baseline and air flow rates up to 50 mL/min. After 10 minutes of air exposure, no measured cytokine levels were elevated. After 24 hours of incubation, cytokine levels of TNFα, IL-10, IL-6, and IL-8 were elevated. However, only IL-8 was significantly elevated in citrated blood, but not in heparinized blood, when compared to baseline samples that were also incubated for 24 hours. CONCLUSION: This study investigates CD11b levels in response to an air stimulus in blood that was anticoagulated with citrate or heparin. Exposure to an air stimulus activates leucocytes. Activation of CD11b was less when using heparin as an anticoagulant compared to citrate. Cytokine activation occurs with air stimulation, but levels do not immediately rise, indicating that time is required to generate free cytokines.

Effect of air exposure and suction on blood cell activation and hemolysis in an in vitro cardiotomy suction model.

Cardiopulmonary bypass (CPB) elicits a systemic inflammatory response. The cause may include surface-induced leukocyte activation and hemolysis. A study was designed to describe the effects of both suction and an air-blood interface independently and in combination on leukocyte and platelet activation, and hemolysis in an in vitro model. Fresh human blood was drawn and tested in four different conditions including control (A), 10 minutes of -600 mm Hg suction (B), 10 minutes of blood exposure to room air at 100 ml/min (C), and 10 minutes of simultaneous suction and air flow (D). Samples were analyzed by flow cytometry (platelets and leukocytes) and plasma-free hemoglobin (PFHb). Leukocyte CD11b expression and platelet P-selectin (CD62P) were analyzed by flow cytometry. In comparison with baseline, granulocytes were significantly activated by air (group C, p = 0.0029) and combination (group D, p = 0.0123) but not by suction alone (group B). Monocytes and platelets were not significantly activated in any group. The PFHb increased significantly in group C (p < 0.001) and group D (p < 0.001). This study suggests that the inflammatory response and associated hemolysis during CPB may be related to air exposure, which could be reduced by minimizing the air exposure of air to blood during cardiotomy suction.